[dygraphs.git] / tests / linear-regression.html

<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href="../css/dygraph.css">
    <title>Linear Regression</title>
    <!--
    For production (minified) code, use:
    <script type="text/javascript" src="dygraph-combined.js"></script>
    -->
    <script type="text/javascript" src="../dist/dygraph.js"></script>

    <style type="text/css">
    body { max-width: 640 px; }
    </style>
  </head>
  <body>
    <h2>Linear Regression Demo</h2>
    <p>Click the buttons to generate linear regressions over either data
    series. If you zoom in and click the regression button, the regression will
    only be run over visible points. Zoom back out to see what the local
    regression looks like over the full data.</p>

    <div id="demodiv" style="width: 480px; height: 320px;"></div>

    <script type="text/javascript">
      var data = [];
      for (var i = 0; i < 120; i++) {
        data.push([i,
                   i / 5.0 + 10.0 * Math.sin(i / 3.0),
                   30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
      }

      g = new Dygraph(
              document.getElementById("demodiv"),
              data,
              {
                labels: ['X', 'Y1', 'Y2'],
                underlayCallback: drawLines,
                drawPoints: true,
                strokeWidth: 0.0
              }
          );

      // coefficients of regression for each series.
      // if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
      // only. The regression line is y = 1 + 2 * x.
      var coeffs = [ null, null, null ];
      function regression(series) {
        // Only run the regression over visible points.
        var range = g.xAxisRange();

        var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
        for (var i = 0; i < g.numRows(); i++) {
          var x = g.getValue(i, 0);
          if (x < range[0] || x > range[1]) continue;

          var y = g.getValue(i, series);
          if (y == null) continue;
          if (y.length == 2) {
            // using fractions
            y = y[0] / y[1];
          }

          num++;
          sum_x += x;
          sum_y += y;
          sum_xy += x * y;
          sum_x2 += x * x;
        }

        var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
        var b = (sum_y - a * sum_x) / num;

        coeffs[series] = [b, a];
        if (typeof(console) != 'undefined') {
          console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
        }

        g.updateOptions({});  // forces a redraw.
      }

      function clearLines() {
        for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
        g.updateOptions({});
      }

      function toHex(rgb) {
        return 'rgb(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ')';
      }

      function drawLines(ctx, area, layout) {
        if (typeof(g) == 'undefined') return;  // won't be set on the initial draw.

        var range = g.xAxisRange();
        for (var i = 0; i < coeffs.length; i++) {
          if (!coeffs[i]) continue;
          var a = coeffs[i][1];
          var b = coeffs[i][0];

          var x1 = range[0];
          var y1 = a * x1 + b;
          var x2 = range[1];
          var y2 = a * x2 + b;

          var p1 = g.toDomCoords(x1, y1);
          var p2 = g.toDomCoords(x2, y2);

          var c = Dygraph.toRGB_(g.getColors()[i - 1]);
          c.r = Math.floor(255 - 0.5 * (255 - c.r));
          c.g = Math.floor(255 - 0.5 * (255 - c.g));
          c.b = Math.floor(255 - 0.5 * (255 - c.b));
          var color = toHex(c);
          ctx.save();
          ctx.strokeStyle = color;
          ctx.lineWidth = 1.0;
          ctx.beginPath();
          ctx.moveTo(p1[0], p1[1]);
          ctx.lineTo(p2[0], p2[1]);
          ctx.closePath();
          ctx.stroke();
          ctx.restore();
        }
      }
      
    </script>
    
    <div style="position: absolute; left: 500px; top: 150px;">
    <input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
    <br/><br/>
    <input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
    <br/><br/>
    <input type=button value="Clear Lines" onClick="clearLines()" />
    </div>
</body>
</html>
Commit	Line	Data
54425b14	1	<!DOCTYPE html>
05a1d116 DV	2	<html>
05a1d116 DV	3	<head>
93a5bb4c	4	<link rel="stylesheet" href="../css/dygraph.css">
05a1d116	5	<title>Linear Regression</title>
7e5ddc94 DV	6	<!--
	7	For production (minified) code, use:
	8	<script type="text/javascript" src="dygraph-combined.js"></script>
	9	-->
fbd6834a	10	<script type="text/javascript" src="../dist/dygraph.js"></script>
7e5ddc94	11
05a1d116 DV	12	<style type="text/css">
	13	body { max-width: 640 px; }
	14	</style>
	15	</head>
	16	<body>
	17	<h2>Linear Regression Demo</h2>
	18	<p>Click the buttons to generate linear regressions over either data
	19	series. If you zoom in and click the regression button, the regression will
	20	only be run over visible points. Zoom back out to see what the local
	21	regression looks like over the full data.</p>
	22
	23	<div id="demodiv" style="width: 480px; height: 320px;"></div>
	24
	25	<script type="text/javascript">
176c94a4	26	var data = [];
05a1d116	27	for (var i = 0; i < 120; i++) {
176c94a4 DV	28	data.push([i,
	29	i / 5.0 + 10.0 * Math.sin(i / 3.0),
	30	30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
05a1d116 DV	31	}
	32
	33	g = new Dygraph(
	34	document.getElementById("demodiv"),
	35	data,
	36	{
176c94a4	37	labels: ['X', 'Y1', 'Y2'],
05a1d116	38	underlayCallback: drawLines,
de0445fc	39	drawPoints: true,
176c94a4	40	strokeWidth: 0.0
05a1d116 DV	41	}
	42	);
	43
	44	// coefficients of regression for each series.
	45	// if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
	46	// only. The regression line is y = 1 + 2 * x.
	47	var coeffs = [ null, null, null ];
	48	function regression(series) {
	49	// Only run the regression over visible points.
	50	var range = g.xAxisRange();
	51
	52	var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
	53	for (var i = 0; i < g.numRows(); i++) {
	54	var x = g.getValue(i, 0);
	55	if (x < range[0] \|\| x > range[1]) continue;
	56
	57	var y = g.getValue(i, series);
	58	if (y == null) continue;
c5a37449 DV	59	if (y.length == 2) {
	60	// using fractions
	61	y = y[0] / y[1];
	62	}
05a1d116 DV	63
	64	num++;
	65	sum_x += x;
	66	sum_y += y;
	67	sum_xy += x * y;
	68	sum_x2 += x * x;
	69	}
	70
	71	var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
	72	var b = (sum_y - a * sum_x) / num;
	73
	74	coeffs[series] = [b, a];
4df1af70	75	if (typeof(console) != 'undefined') {
2a07b0ad DV	76	console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
2a07b0ad DV	77	}
05a1d116 DV	78
	79	g.updateOptions({}); // forces a redraw.
	80	}
	81
	82	function clearLines() {
	83	for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
	84	g.updateOptions({});
	85	}
	86
0a171c09 DV	87	function toHex(rgb) {
	88	return 'rgb(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ')';
	89	}
	90
05a1d116 DV	91	function drawLines(ctx, area, layout) {
	92	if (typeof(g) == 'undefined') return; // won't be set on the initial draw.
	93
	94	var range = g.xAxisRange();
	95	for (var i = 0; i < coeffs.length; i++) {
	96	if (!coeffs[i]) continue;
	97	var a = coeffs[i][1];
	98	var b = coeffs[i][0];
	99
	100	var x1 = range[0];
	101	var y1 = a * x1 + b;
	102	var x2 = range[1];
	103	var y2 = a * x2 + b;
	104
	105	var p1 = g.toDomCoords(x1, y1);
	106	var p2 = g.toDomCoords(x2, y2);
	107
0a171c09	108	var c = Dygraph.toRGB_(g.getColors()[i - 1]);
34bbe78b DV	109	c.r = Math.floor(255 - 0.5 * (255 - c.r));
	110	c.g = Math.floor(255 - 0.5 * (255 - c.g));
	111	c.b = Math.floor(255 - 0.5 * (255 - c.b));
0a171c09	112	var color = toHex(c);
05a1d116 DV	113	ctx.save();
	114	ctx.strokeStyle = color;
	115	ctx.lineWidth = 1.0;
	116	ctx.beginPath();
	117	ctx.moveTo(p1[0], p1[1]);
	118	ctx.lineTo(p2[0], p2[1]);
	119	ctx.closePath();
	120	ctx.stroke();
	121	ctx.restore();
	122	}
	123	}
	124
	125	</script>
	126
	127	<div style="position: absolute; left: 500px; top: 150px;">
	128	<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
	129	<br/><br/>
	130	<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
	131	<br/><br/>
	132	<input type=button value="Clear Lines" onClick="clearLines()" />
	133	</div>
	134	</body>
	135	</html>